1. Field of the Invention
The present invention relates to a webbing retractor for winding up a webbing for restraining an occupant in an emergency in a vehicle, and more particularly to a webbing retractor for obtaining improved fitness.
2. Description of the Prior Art
For the webbing retractors for restraining the occupant in an emergency in a vehicle to secure safety for the occupant, such an arrangement is commonly used that the remaining portion of the webbing for restraining the occupant is wound up in the retractor by a biasing force.
Additionally, in the retractor, there has been provided an inertia-lock mechanism which senses the emergency of the vehicle and instantly stops winding out of the webbing, whereby it is possible for the occupant to wind out the webbing from the retractor against the biasing force in a normal running condition of the vehicle, thereby enabling the occupant to move freely.
However, with the conventional retractor as described above, there has been pointed out a disadvantage that, when the vehicle runs on a bad road and the like, the retractor gradually winds up the webbing to take up any slight slack between the occupant and the webbing, which is necessary for maintaining pleasant running condition, whereby a tension, i.e., an oppressive sensation given the occupant by the webbing, is gradually increased.
This condition is because the vehicle is vibrating, the vibrations actuate the intertia-lock mechanism, and hence, it is impossible to wind out the webbing from the retractor, and, every time the occupant moves, the retractor advances a ratchet included in the inertia-lock mechanism pitch by pitch by the biasing force of a spiral spring, whereby the occupant is gradually oppressed as if caught in an automatically tightening snare. Namely, at the time when the vehicle vibrates, the inertia-lock mechanism functions as an automatic retractor capable of merely winding up the webbing.